Automatic focusing system

Claim 2

An automatic focusing system comprising: a) detecting means for detecting a signal which varies with the state of focus; b) computing means arranged to collate detec­ted information output from said detecting means with preset and predetermined conditions and to output control information for controlling the state of focus on the basis of a degree to which said detected information conforms with said preset conditions; c) condition setting varying means for varying the setting of said conditions; and d) focus adjusting means for adjusting focus on the basis of said control information output from said computing means.

Claim 3

A system according to claim 1, wherein said focus adjusting means includes a focusing lens.

Claim 4

A system according to claim 1, further comprising image sensing means arranged to convert an object image into an image signal, and wherein said detecting means is arranged to extract, from said image signal output from said image sensing means, a high-frequency component and an edge signal corresponding to the width of an edge part of the object image.

Claim 5

A system according to claim 1, wherein said con­ditions are plurally arranged, and wherein said computing means is arranged to collate a plurality of pieces of information including said detected information output from said detecting means with said preset conditions and to obtain a control information signal for driving and controlling said focus adjusting means by computing degrees to which said plurality of pieces of information conform with said preset conditions.

Claim 6

A system according to claim 4, wherein said con­trol information signal is information on a driving speed at which said focus adjusting means is to be driven.

Claim 7

A system according to claim 4 or 5, wherein said computing means is arranged to obtain, from a plurality of membership functions, degrees to which said plurality of pieces of information conform with a plurality of pre­set and predetermined rules through computation and to obtain and produce said control information signal by performing a computing operation using a fuzzy infer­ence algorithm on the basis of the result of said computation.

Claim 8

A system according to claim 6, wherein said con­dition setting varying means is arranged to vary said con­ditions according to the state of an object image.

Claim 9

A system according to claim 7, wherein said state of an object image is the contrast of the object image.

Claim 10

A system according to claim 8, wherein said con­dition setting varying means is arranged to vary said con­ditions in such a way as to cause a focus adjusting speed of said focus adjusting means to be lowered by correcting the result of the computing operation of said computing means when the object image is of low contrast.

Claim 11

A system according to claim 9, wherein said con­dition setting varying means is arranged to vary said con­ditions in such a way as to cause a focus adjusting speed of said focus adjusting means to be heightened by correcting the result of the computing operation of said computing means when the object image is of high contrast.

Claim 12

A system according to claim 10, wherein said condition setting varying means is arranged to vary said membership functions.

Claim 13

A system according to claim 10, wherein said condition setting varying means is arranged to vary said rules.

Claim 14

A control device comprising: a) detecting means for detecting information which varies with the state of a controlled object; b) computing means arranged to collate the detected information output from said detecting means with predetermined conditions and to obtain by computation a control signal for controlling said controlled object on the basis of the probability that said information conforms with said predetermined conditions; and c) setting varying means for varying said conditions to correct said control signal.

Claim 15

A control device comprising: a) detecting means for detecting information which varies with the state of a controlled object; b) computing means arranged to collate the detected information output from said detecting means with predetermined conditions and to obtain by computation a control signal for controlling said controlled object on the basis of the probability that said information conforms with said predetermined conditions; and c) setting varying means for varying said conditions to correct said control signal.

Claim 16

A device according to claim 13, further compris­ing driving means for driving said controlled object on the basis of the control signal output from said computing means.

Claim 17

A device according to claim 14, wherein said conditions are plurally arranged, and wherein said com­puting means is arranged to obtain the probability that the detected information output from said detecting means conforms with said conditions and to obtain said control signal by performing computation on said probability obtained.

Claim 18

A device according to claim 15, wherein said computing means is arranged to obtain, from a plurality of membership functions, degrees to which said plurality of pieces of information conform with a plurality of pre­set and predetermined rules through computation and to obtain and produce said control information signal by performing a computing operation using a fuzzy infer­ence algorithm on the basis of the result of said computation.

Claim 19

A device according to claim 16, wherein said setting varying means is arranged to correct said membership functions.

Claim 20

A device according to claim 16, wherein said setting varying means is arranged to vary the contents of said rules.

Claim 21

A device according to claim 17 or 18, wherein said setting varying means includes detecting means for detecting the environment of said controlled object and corrects said conditions according to said environment.

Claim 22

A device according to claim 19, wherein said controlled object is a photo-taking lens of a camera.

Claim 23

A video camera comprising: a) image sensing means for photo-electrically converting an object image to output an image signal; b) focus detecting means for detecting, from said image signal, a signal which varies with the state of focus; c) computing means arranged to collate information detected by said focus detecting means with a plurality of preset rules, to obtain the probability that said detected information conforms with said rules by using predetermined functions, and to output focus con­trol information by computing information on said probability; d) focus adjusting means for varying the state of focus on the basis of said focus control information output from said computing means; e) signal detecting means for detecting, from said image signal, a predetermined signal which indicates the state of the object image; and f) correcting means for correcting, on the basis of said predetermined signal output from said signal detecting means, the result of computation of said computing means by correcting at least either said rules or functions used by said computing means.

Claim 24

A video camera comprising: a) image sensing means for photo-electrically converting an object image to output an image signal; b) focus detecting means for detecting, from said image signal, a signal which varies with the state of focus; c) computing means arranged to collate information detected by said focus detecting means with a plurality of preset rules, to obtain the probability that said detected information conforms with said rules by using predetermined functions, and to output focus con­trol information by computing information on said probability; d) focus adjusting means for varying the state of focus on the basis of said focus control information output from said computing means; e) signal detecting means for detecting, from said image signal, a predetermined signal which indicates the state of the object image; and f) correcting means for correcting, on the basis of said predetermined signal output from said signal detecting means, the result of computation of said computing means by correcting at least either said rules or functions used by said computing means.

Claim 25

A video camera according to claim 21, wherein said focus detecting means is arranged to detect, from said image signal, a high-frequency component and a signal related to the edge width of the object image.

Claim 26

A video camera according to claim 21, wherein said preset rules are plurally arranged, and wherein said computing means is arranged to collate a plurality of pieces of information including detected information output from said focus detecting means with said preset rules and to obtain a control information signal for driving and controlling said focus adjusting means by computing degrees to which said plurality of pieces of information conform with said preset rules.

Claim 27

A video camera according to claim 23, wherein said focus control information relates to a driving speed at which said focus adjusting means is to be driven.

Claim 28

A video camera according to claim 23 or 24, wherein said computing means is arranged to compute a control signal with a fuzzy inference by using said plu­rality of rules and functions.

Claim 29

A video camera according to claim 21 or 25, wherein said signal detecting means is arranged to detect the contrast of the object image from a luminance signal included in said image signal.

Claim 30

A video camera according to claim 26, wherein said correcting means is arranged to correct said func­tions in accordance with said contrast.

Claim 31

A video camera according to claim 26, wherein said correcting means is arranged to correct said rules in accordance with said contrast.

Claim 32

A camera according to claim 27 or 28, wherein said correcting means is arranged to correct the result of computation of said computing means in such a way as to lower a focus adjusting speed of said focus adjusting means when the object image is of low contrast.

Claim 33

A video camera according to claim 29, wherein said correcting means is arranged to correct the result of computation of said computing means in such a way as to heighten the focus adjusting speed of said focus adjusting means when the object image is of high contrast.

Claim 34

A focus control circuit arranged to recieve a plurality of focus responsive signals and to generate a focus control signal in dependence upon a predetermined combination of the focus responsive signals, characterised in that it includes means for varying the predetermined combination.

Claim 35

A focus control circuit arranged to recieve a plurality of focus responsive signals and to generate a focus control signal in dependence upon a predetermined combination of the focus responsive signals, characterised in that it includes means for varying the predetermined combination.

Claim 36

A circuit according to claim 31, further characterised in that it includes means for deriving a signal which differs between different objects to be focused upon, in a like manner to object-related differences in the focus responsive signals, and the means for varying the predetermined combination is arranged to do so in dependence upon the object responsive signal in such a way as to reduce the object-related dependence of the focus responsive signals.

Claim 37

A device according to claim 31 in which the object-related signal is a contrast signal.

Claim 38

A focus controller in which the focus is responsive to image contrast.

Claim 39

A focus controller in which the focus is responsive to image contrast.

Claim 40

A motor driven focus control system in which the motor speed is responsive to image contrast.

Claim 41

A motor driven focus control system in which the motor speed is responsive to image contrast.